The subject invention concerns a truck which is adapted to handle loading pallets with the aid of fork-shaped lifting arms which are provided with vertically movable support wheels and with driving wheels arranged to pivot to steer the truck. Within the scope of the invention, the truck claimed herein may be designed as a guided truck in which case it is operated by a person walking beside the truck, it may be used as a driver-operated truck, the driver either sitting or standing on the truck, or it may be designed as an automatically guided truck, such as a loop-operated truck.
Prior-art trucks are primarily constructed to lift and transport one or two loading pallets (usually so called EUR-pallets) on a flat ground or support. However often the ideally flat-level conditions do not exist. For instance, it is often desired to use trucks to lift pallets on and off lorry loading-platforms. In order to lift off the pallets, the truck is driven onto the lorry loading-platform from a loading bridge or the like. To span the loading bridge and the loading platform a sloping drive-on ramp usually has to be employed, since the loading-platform and the loading bridge rarely are on the same level. When a conventional truck is driven onto a sloping ramp of this kind its lifting forks will be tilted upwards (or downwards) relative to the lorry loading-platform and consequently it presents considerable difficulties and may even be impossible to insert the lifting forks underneath the pallets as the spaces provided for this purpose are quite restricted vertically.
Loading of lorries by means of conventional trucks is also made additionally difficult in that lorry platforms seldom are horizontal but usually slope somewhat. This increases the difficulties of inserting the lifting forks into the space underneath the loading pallets. One purpose of the subject invention is to provide a truck which is capable of operating on sloping grounds or levels.
A problem which is encountered when pallets are loaded onto lorry platforms from behind is the highly restricted space laterally on the platform. Obviously, it is an advantage if optimum use can be made of this space. When loads are deposited on or lifted off platforms, precision in handling the pallets on the platform therefore is an important consideration. A problem arising in this connection is the risk of the occurrence of the phenomenon known as the sticking drawer effect, that is, the risk that when one operates in very narrow and restricted areas, one pallet, box or similar object will assume an oblique position relative to the rest and get stuck. To avoid this problem one of the purposes of the subject invention is to provide a truck which is capable of precision-handling loads, also in very restricted and narrow areas.
Trucks designed in accordance with conventional technology are normally equipped to handle one pallet of standard dimensions or possibly two such pallets stacked one on top of the other. This limits the capacity of prior-art trucks as well as entailing disadvantages of logistics which, taken together, in the case of a lorry and/or a trailer bring about comparatively lengthy loading-on and loading-off times as well as long truck operating times. Another purpose of the subject invention therefore is to provide a truck the capacity of which is greatly improved over that of prior-art trucks. The truck in accordance with the invention is designed to handle a large number of pallets of standard size (up to nine EUR pallets positioned side by side) or a smaller number of large-size pallets of a special design. The larger the individual pallet the larger the problems of steering and controlling the truck when it is to be driven onto and deposit its load on the loading platform.